Centrifugal separator



' Feb. 25, 1941.

W. BUDDEBERG CENTRIFUGAL SEPARATOR Filed May 4, 1938` ATTORNEYS Patented Feb. 25, 1941 'CENTrIFUGAI'.V sEARToR Walter Buddeberg, Ravensburg, Germany; asfsignor to Albert T.' Otto & Sonsyln'c.,l New York, l

N. Y., acorporation'of New York f :f 'Appmioniwaya 1938,?Siaiimaoassi. f 1

VIn Swit:z e'rland Junell, 1931, y n sclaims. (ci.- 210513) e y e y A materialvisslfted tolthe highercentrifugal K forcfesfproduced in the.main drum'of the cen` trifugalseparati'.

This invention relates to a centrifugal'machine for separating "mixtures and particularly to that type of centrifugal machine or separator which' is designed for continuous operation.,r as icon# trasted withI batch operation.

Centrifugal machines designedfor lthe separation of liquids and solids either by centrifugal sedimentation or centrifugal filtration areusually charged through astationary inlet pipe arrangedl to permitthe mixture to be treated toiiow into the rapidly rotating'separating drum of thetmachine. As the mixture leaving the inlet pipe strikes the surfaceof .the rotating drumor the layer of material l mixture suffers a severe shock because these marequired maximum to produce the desired eilect.r

This slowing down and speeding up of themachine is highlyundesirable :because it requires additional power, imposes additional Hstrairron vthe mechanism and increases'the time for carry--v ying `out the process. This method vof operation is little. better-than the batchV loading method, and therefore. the advantages of the continuous operation at high speed is.to a great-'extent lost,

with the-result that many i'riable and slow draining materials have not been processed in, con`l tinuous centrifugals becausev of breakage orjinability to accomplish even loading. n

o The present invention overcomsthese diiiicul-k ties and limitations and more efficient use of continuous centrifugal machines. lAn object of this invention isto produce a lmachine of' the continuouscentrifugal vtype wherein the mixtureto be treated will be taken from'a stationary inlet'pipe and subjected to a gradually increasing rotational speed until it ar-v rives at or approaches substantially the same rotationalspeed as the separating drum, when itis deposited on said drum in a uniform 'annular deposition. f `v Another object of the invention is to produce a mechanism which will give the material to be treatedv :tf-preliminaryV centrifugal 'action of a lesser extent'- than the final actionbefore the already collected therein, vthechinesA operate at a. very high rotational speed.A

permits a wider` `and v A further l, object of the inventionr is, to `'disftribute".they mixture' ton-bentreatedevenlyfpver 5 theinterior of'` the rotatableV Separating drum. 1

]Another advantage of the *construction herein disclosed islfthat theconical rotatable distributor g which conveys the' material to be treated vfrom the inlet pipeto'the separating drum is of relatively 10 g large cross-sectional arealand acts morerl less like a reservoir-so that ,slightY variations'infflow *throughl 'the charging pipe,r or even momentary interruptionsfare compensated for and uneven 'distribution' of the jmaterial'ron the vd lumji's '15 avoided; Y 'fig T 'f A'further: advantageof thegpresentyconstruc ktion is that thesmallen'd of the conical' distrib-.

utoror ltheferid which receives thedischarge `from theinlet pipe may be located outside of` the 20 housingA for the" separating drum' sof that any overcharg'e for excessive materiali will spill lntoa surrounding 'casingor gutter outside y'of thefmain centrifugalhousingand canbe 'piped away'without aifecting the' centrifugal"separationlopeaf 25 "The'dispositionof theV conical distributo'rrwith'-,A` f in the separating :drum results in a very compact space i saving design because-'the material' acted uponpassestaxiallyhalongrthe interiocf the v30 distributor and then back'in theopposite direc'-Y tion along the interiorfof the drum-,thus produc-` ingwhat may-be termed; a two-pass operation; Besides compactness, this .design lends' itself to accessibility-and whenthe casing is 'furnished 35 with -windowsthe various par-tsmay be seen'in operation. ,y e Avnal object of this inventionfis to utilize the.

centrifugeeiectvaof .the separating .drum tothe. n*

best. advantage by deliveringv the mixtureto be 40- treated to this drum at, substantially thefsame f 'rotational -speedf asthe .drum` itself, possesses, l so Lthe present devienne higiijspeed separating', ac'- tion dueto thecentrifugal ViOrcesset lupzin the f mixture commences towork as soon as the .mix-f?l ture leaves;l the distributorfand reaches ,the sepa..-`l`

rating .4, d ,50 In the accompanying drawing are-illustrated certain embodiments oftherinvention, butzitwill.y s

Fig. 2 is a side View, partly in section, of onel end of a centrifugal.machinef-showing another embodiment of the invention.

Fig. 3 is another side view, partly in section, y

of one end of a centrifugal machine showing ,a third embodiment of the invention.'

Looking at Fig. 1, the centrifugal machineil lustrated therein comprises a base i upon which is mounted a pair of supporting bearings-3 and 4 which are adapted to rotatably receive the lmain shaft 5, upon which the separating drum 6 is mounted. This drum consists of a fixed end wall 1 keyed to shaft 5 and adapted to rotate therewith, and a perforated cylindrical portion l attached to said end 4wall l to form a horimntally disposed cylinder closed at onezend. kRotatable separating drum B isvsurrounded by acasing il adapted to collectv the liquidr or other material 'thrown foff by the rapidly rotating drum and deliver it to an'outletpipe Il attached to-the bottom of casing I0. A casingi surrounds the space adjacent to the. end of drum I so that solid material which is moved outwardly 'and axially from the interior. of the separating. drum will be collected anddelivered tovoutlet Il. Main shaft 5 is internally bored to. slidably receive Yshaft |I`which is keyed to shaft 5 with a sliding key I lso that both shafts rotate togethenbut the-latter may move axially in regard tothe former. Shaft I! is equipped with a piston I2 operating in a cylinder` I8 attachedto and formed as part Vof the main shaft v5. lShaft Il is internally bored to form a passageway 20 which cornmunicates through suitable openings 2| withthe space on the right side of the pistonv il, as viewed in Fig.` l. `A slmilarpassageway 2l.' between the two shafts furnishes communication with the other side of the piston. These passageways are for the purpose of introducing liquid under pressure to move the piston il relative to the cylinder II, as is well known in the art. i

Upon the right end of shaft Il is keyedV a'movable end wall 22 of but slightly less diameter than the inside of the drum. l. By the introduction of liquid under pressure into the cylinder i!A on one side or the other of piston il, the end wall 22 maybe moved axially in relation to the drum l through 'a limited distance, which' movement will serve topress the'solid materiall collected on the interior of the drum 8 outwardly or to the right, as viewed in the figure. so that it is forced out of thedrum and into the casing Il.

, In normal operation, the reciprocal motion of the end walliscontinuous. y i A `Attached to the movable end wall 22 is a conical distributor 2B so arranged that the larger diameter end is adjacent tothe end wall 22 but spaced therefrom by the'attachment lugs 26 so as v to provide a passageway between the distributorV and the' end wall 22 forfthe radial discharge of the material being treated from the distributor onto the interior of the separating drum I. The smaller diameter end of the distributor projects out through the casing Itand into acasing 28 which is equipped with a discharge pipe 29. This construction permits any "excess e material in the distributor to overflow linto the`caslng 2l and to be carried away through the pipe '25. Inlet pipe 20 is arranged to convey the material to be treated through the casing 28 into the smaller diameter end of the distributor 25, as illustrated in the drawing.

In operation the drum i, the end wall 22 and i the distributor 25 are rotating together at a high speed.. The material to be treated is admitted f through the inlet pipe l0 and will deposit itself `in thevreceiving chamber, but it will probably be much nearer to the inside diameter of the small end'than ofv the' large end of the distributor. As the material reaches the large end of the 4distribi'itor and is moved out by centrifugal force toward the periphery thereof, it will attain a linear velocity (which shall be understood to mean, when used in describing the operation of applicants present machine, the velocity of a particle yat any instant along, a tangent to its curved path of movement, and the centrifugal forceexerted on the particle varies as the square of thisvelocity) substantiallyl the same as the linear velocity of the inner Vsurface, of the separating drum, so that as thematerial leaves the distributor and is' deposited on, the drum, there is little or no change inlinear velocity.. 0n the other` hand,

due to the inclination ofthe side walls of the conical distributor. the small diameter end of the distributor is nearer ythe axis of rotation and therefore will have a considerably lesser linear velocity. `y f The material asit passes from the pipe 2l to the wall ofthe inner end of the distributor moves `only a very short distance radially so that the impact is'small and as it moves toward the larger end it gradually acquires the linear velocity of .thedistributor andthere is little or no impact or disturbance las it passes from the distributor to the drum.

`The distributor ismoved back'and forth axially `with the scraper wall 22 so that as the wall moves toward the right it pushes material` axially of kthe drum and asit moves toward the left the space at me left or the material remaining 5 inthe drum isnlled with fresh unseparated matenai. Y y

Fig. 2 -lllustrates lanother embodiment of the invention wherein those parts of the mechanism i which are the same as illustrated in Fig. 1 will be given the same numeral with the addition of That portion of the machine not illustrated is the same as the corresponding portion shown inFlg..l.f i i The main shaft Nlcarrles the separating drum |06. This drum consists of a hired end wall I" keyedto sh'aft illjand a `perforated cylindrical `drum ill. "The separating IllI is surroundedby casing IIB which is adapted tocolleeft the liquid thrown of! from the basket and deliver itthroualrn discharge pipe l I I. An outer casing HI surrounds the space outside the end of separating drum` lill and collects solid material expelled therefrom and deposits it in discharge pipe ill. shaft I" is hollow and slidably keyed therein isshaft `I Il which is adapted to be moved backfand'forth` axially by a suitable piston 1and, cylinder as shown in Fig. 1. On shaft III which -protrudes into the separating'` drum IM is mounted ja disc |22 which acts to axially `move the material in the seimrating` drum lll. This disc is keyed to shaft i I5 and rotates with it, and as shaft IIS in turn is slidably keyed to shaft IIIS upon which the separating drum IIB is y y y 2,232,768 mounted the drum, the two shafts and the end wall |22 all rotate together.V

On an extension of shaft H beyond the movl able end wall |22 is mounted a conical distributor |25. The distributor' is supported on arms |26 and is so arranged that the end of larger diameter is adjacent to, but spaced from the movable end wall |22, so ,that material to be treated which is .fed into the distributor may fiowby centrifugal action between theend wall |22 and thelarger peripheral end of the'distributorv ontotherinside of the drum |06. A delivery inlet. pipe is adapted todeliver vthe material to be treated into the smaller diameter end of the distributor |25.

lIn `operation the material passes through the inlet pipe .30 into the. smaller end of the distributor |25 and forms a hollow truncated c'onetherein. Because of the sloping walls of the distributor and the centrifugal force'setup by its rotation, the material moves along the distributor from the snfialler end towardthe end of larger diameter'and is nally `forced' out between the distributor and the end wall on tothe inner surface of the drum |08. The movable endplate |22 may be moved back and forth toexpel thesolid material, as is now well known in the art.

i end wall |22.

Thedistributor at its large vdiameter end has an annular flange at the outer periphery, extendvoi the material.I `This .flange serves as a support for the material fillingfup between the end wall E22 and the distributor, so that during the return stroke of said end walLthere will be radequate material to prevent the formation of any gap between the outer cornerof the distributor 'and the centrifuged partially dried cake of material remaining on theinner periphery of the drum. It thus prevents any by-pass of fresh liquid material from the distributor to the discharge casing. The distance between theend wall |22 and the nearest section of the distributor |25 is substantially greater than the length of the stroke `of the Thus, at the end ofthe return stroke of the end wall |22, firm and partially dried centrifuged material remaining on', the` linner periphery of the drum -extendsrinwardlybeyond the distributor |25, and serves `as a plug to prevent the fresh fluid. material from by-passing from said distributor to the discharge casing.

'I'his embodiment has many of the advantages pointed out in regard to the construction illustrated in Fig. 1, that is, the material emerging from the end ,of the inlet pipe |30 engagesl the portion of the'distributor which is traveling at the lowest linear velocity because of thesmaller diameter and then travels along'the distributor toward the end of larger diameter, and'as it does so, its linear velocity increases due to the-fact that it is moving further and further from the center of rotation and finally, as the material Vpasses off the distributor and onto thev inside of `the drum, it possesses substantially the lsamey stead, the supporting arms for the distributor are attached at a point intermediate; the endsthereof where the velocity oi' the material passing through the distributor is not so great as it is charge therefrom at 2| I. itself -is shown'at 206 `and the xed end wall when'it reaches the space between the larger end of the distributor and the movable end wall. This is of lsome advantage'when working with fibrous materials which might be apt to collect aroundv supporting arms placed immediately adjacent tothe discharge end of the distributor.V

When the arms. are positioned as illustrated in 4 this embodiment, any fibers caught on the arms will be dislodged by the continuingcharge of material" with its relatively highv liquid content at this stage of the operation'and thereis an opportunity for the solid material to reearr'an'g'e it-y y arating drum and it is not intended that thefinvention be limited to attachment tothe end wall or the shaft upon which said Wall'is'mounted.

Fig. 3 shows still Vanother embodiment of the I invention wherein the rotating separating -drum and the movable end wall are supported'iand actuated by the same mechanismas that 'shown in Fig. 1, heretofore'described. Elements-in Athis construction similar to those shown in Fig. l' will be designated bythe same numeral with the addition of 200.

The base of the centrifugal machine'is shown at zal, the main Supporting Simfree zusA and the internall shaft slidably keyed to theshaft' 205and supporting'at the end thereof the movable'end wall 222 is shown at 2 5. The casing surrounding the separating drum is shown at 2 I0 and the disthe-drum consists of the iixed end Vwall 201 The separatingdruml mounted on the shaft 205 and the cylindrical per- The internal shaft 2 5 is adapted to move the end wall 222 axially back and forth through a limited distance to assist in the discharge of the solid`- -material from the inner wall of the separating vi'oratedbasket 208 mounted on the end wall 207.

drum, as heretofore described. Casing 2|3sur-"I' rounds the outside end of the drum and is adapted torcollect solid material discharged therefrom'and deposit it in discharge pipe 2 I4. In this embodi- Vment of the invention, theconical distributor 225.l

is supported on roller bearings'226 on the endof tate at a relatively high speed as in the embodiand 2, but the distributor 225 is not positively driven but instead is freely mounted to rotate on the ball bearings 22B. on bearings attached tothe'casingor some other The distributor may Vrotate -ments heretofore described in relation to Figs. 1:;

stationary part of vthe mechanism and it is not intended that the inventionbe precise construction shown.

In operation the material to be' treated passes through the delivery pipe 230 and into the smaller limited 'to' `the,

diameterfend of the distributor 225. At first itv 'passesdown by gravityalong the inclined wall until it fills the spacebetween the rotating movable wall 222and thelarger end of the distributor L220 when the friction willthen cause the distributor 225 to rotate, and, as it does so, lthe incomingmaterialwillbe whirled around to cover all of the inner wall of the distributor 225 and finally'- illl thev annular space between the distribi utor and/the movable end wall so that the matef rial itself will act as a binder between the rapidly-1`v` rotating end wall and the distributor and cause the latter to rotate at a high speed, with the eiiect that as the material leaves the distributor, it possesses a rotational velocity approaching that of the inner wall of the separating drum 2M. In this construction, as in the two previous embodiments described and illustrated, the incoming material engages the small diameter end of the distributor which has a minimum linear velocity, and as it progresses along the inclined walls of the distributor, its linear velocity increases because of the increased distance from the axis and finally, as it is discharged between the distributor and movable end wall, it has acquired a velocity approaching .that of the separator drum, with the result that it can engage the drum or the material thereon with a minimum of shock and damage.

'I'he advantage of this particular construction is that the flow of material being treated from the inlet pipe 230 to the separating drum is entirely unobstructed and free.` There is nothing to arrest the solid particles as they travel through the distributor and nothing which might tend to cause an uneven distribution on the drum 206.

With free-draining solids from which the surroundingliquid is quickly removed by centrifugal force so that ythe mixture being processed changes quickly from a somewhat fluid state to that of a well-formed cake of solids, it has been discovered that the centrifugal operates to best advantage when the inlet funnel is located so that the space between it and the pusher is kept small. so that too much material is not allowed to pass from the funnel into the main drum, and thus obtain even and gradual filling of the drum.

It is sometimes desirable to maintain a certain quantity of solid material on the interior of the separating drum. This can be accomplished by making the distance between the large diameter end of the distributor and thel movable end wall longer than the axial stroke of the wall so that the end wall will not clear ofi' that entire space when it moves to the right, as viewed in the figures, but instead will only clear part of it and the remaining part will serve as a filter for the smaller particles and will also serveto enable a new layer to be built more readily on the cleared portion of the interior of the drum. This proportioning of the stroke of the movable wall and the distance between the large diameter end of the distributor and said wall depends upon the character of material being worked upon.

On the other hand, if the mixture is of such character that it is desirable to have little solid matter on the interior of the separating drum adjacent to the outlet of the distributor, the stroke of the end wall can be made equal to or greater than the distance between the end wall and the large diameter end ofthe distributor. In such a construction the liquid in the'mixture would have little solid matter to pass through on the inside of the drum adjacent to the outlet from the distributor and therefore it could quickly pass through the drum wall into the liquid collecting casing.

The thickness of the layer of solid material deposited on the interior of the separating drum may be regulated by the relative diameters of the large end of the distributor` and said drum. The space between the two will define this dimension. The thickness of the layer of solid material left on the interior of the separating drum` in the area covered by the movable end wall can be governed by the clearance between the end wall and the interior of the separating drum and the area cleared by the movable end wall and the relation of the width or length of thlsarea to the width of the space between the movable end wall and the large end of the distributor can be varied to control the amount of solid material left .on Ithat portion of the interior of the separating drum immediately under the discharge end of the distributor.

Some modifications. may advantageously be made in the shape ofthe lip on the larger diameter end oi thel distributor. It may be made sharp or with an annular lip parallel tothe cooperating end wall (Fig. 1) or itmay even be made with a backward slope as illustrated in Figs.

-2 and 3. This latter construction has been found advantageous in handling substances with an angle of slope, such as salts, for it prevents the formation of an opening between the outer edge of lthe distributor and the layer of material deposited on the inner surface `of the drum.

In the construction shown in Fig. l, the conical distributor is of a length greater than that of the drum, and its wall is of an angle of about 30 to the axis. A somewhat steeper angle is shown in Figs. 2 and 3 but the angle should not be so steepbut what the material will take an appreciable time and have a relatively low speed in an axial direction while moving from the small end to the large end and gradually requiring the linear velocity of 4the drum surface or the accumulated layer thereon. Ordinarily the angle is not much in excess of 45. `This will depend somewhat on the relative length and diameter of the drum. The imperi'orate wall of the distributorA preferably has a smooth inner surface so thatthe material may slip or drag behind in a rotational direction `while requiring the rotational velocity of the part of the distributor wall with which Vit isin 'contact and while moving in an axial direction.

By these `variations suggested. a machine of the type herein disclosed can be adapted for a large variety and character of mixtures so that its field of usefulness is greatly extended.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is: i

1. A centrifugal machine having a rotatable drum, an axially movable end wall for said drum, rotatable'with said drum, and adapted to discharge the centrifuged material from the inner periphery of said drum, a material inlet, and a rotatable conical distributor arranged to receive the discharge from said inlet into the small diamveter end thereof and deliver it from the large diameter end whichis adjacent to but spaced Ifrom said movable end wall, the large diameter end of said distributor `forming with said end wall an annular channel for delivery of the material from said distributor to the inner periphery of said drum, the outer periphery of said end wall extending radially outwardly beyond` the outer periphery of the large diameter end of said distributor. V

2. A centrifugal machine including a rotatable drum having an end wall, rotatable with said drum and axially movable to discharge the centriiuged material from the inner periphery of said drum, a conical distributor attachedto said end wall so as to rotate therewith and so arranged that the larger diameter end of said conical distributor isadiacent to but spaced from said end wall and forms -therewith an` annular channel for delivery of the material from said distributor to the inner periphery of said drum,

being spaced radially inwardly from the outer periphery of said end wall, and a material inlet arranged to discharge into the smaller diameter end of said distributor.

3. A centrifugal machine having a rotatable drum, a stationary material inlet, a conical distributor attached .to said drum and arranged to receive from said inlet the material to be treated at the small diameter end thereof and deliver'it to said drum from the large diameter end, a casing at the discharge end of said drum, having an outlet from which the centrifuged material is discharged from said drum, and a second casing at the outer end of said first casing, and having a discharge outlet, the small diameter end of said distributor projecting through said first casing and into said second casing, whereby said latter casing collects any excess material which mayI overflow from said distributor.

4. A centrifugal machine including a rotatable separating drum having an end wall axially movable to discharge Ithe material from the drum, a material inlet pipe for lthe mixture to. be treated co-axially arranged in relation to said drum and a conical distributor rotatably mounted on said inlet pipe with the smaller diameter end thereof encircling said pipe and the larger diameter end adjacent to but spaced from said end wall so that material passing into said distributor will be subjected to preliminary centrifugal action to impart to it a linear velocity substantially equal to that of the separating drum as the material is transferred from the distributor to the drum.

5. A centrifugal machine having a rotatable separating drum, an axially movable end wall therein, a conical distributor in said drum,y,co axial therewith and having its large diameter end spaced from said end Wall to form an annular discharge passage between said wall and said distributor, arms connecting said end wall to said distributor, and spaced a substantial distance inwardly from said passage, and a material inlet adapted to discharge into the small diameter end of said distributor.

6. A centrifugal machine having a rotatable separator drum, an axially movable end wall therefor, a rotatable conical distributor having the larger diameter end adjacent to the inner periphery of said drum, and adjacent to but spaced from said end wall to. form anannular passage for the delivery of material from said distributor to said drum, said larger diameter end having an annular flange forming a wall of ysaid Passage, and extending obliquely radially outwardly away from said end wall to permit piling of the material against said ange, and the smaller materialreceiving end of said distributor being adjacent to the discharge end of the drum opposite to said end wail.

7. A centrifugal machine including a rotatable separator drum open at one end, and having an' end wall at the other end, means for moving said end wall axially in said drum to push centrifuged material along the innerperiphery of said drum to said open end, a rotatable conical distributor having its smaller material receiving end at the open end of the drum, and its larger end adjacent to the inner periphery oi' said drum; and adiacent to but spaced from said end wall to form an annular passage for lthe discharging material from said distributor lto the inner periphery of said drum, the smallest distance between said distributor and said end wall being larger than the stroke of said end wall. t

8. A centrifugal machine vhaving a drum mounted for rotation about a horizontal axis having a perforated peripheral wall, a piston movable axially within said drum fordischarging the. centrifuged material, said piston having aconical funnel secured thereto and axially spaced therefrom a substantial distance for directing material toward the periphery ofthe drum, and means for feeding said material into the interior o1' said funnel near the smaller end thereof and between said piston and said funnel. o

9. A centrifugal machine including a horizontally disposed power shaft formed of two coaxial sections, one of. which is hollow, a cylinder interposed between and connected to said sections y to rotate therewith'. a' centrifugal drum connected to one end of the hollow section and having a perforated peripheral wall, a piston within said cylinder, a'n end wall within said centrifugal drum, a rod extending through said hollow shaft section and connecting'said piston and said "end wall whereby -said end wall may be moved axially in said centrifugal drum by the action of said piston, means preventing relative rotation oi' said rod, piston and end wall in respect to said hollow shaft, cylinder and drum, but permitting axial movement thereof, and means for delivering material to said drum adjacent to said perforated peripheral wall and adjacent to said axially movable end wall.

WALTER BUDDEBERG. 

